The present invention relates to a karaoke apparatus for sounding a requested karaoke song containing an instrumental accompaniment part and a back chorus part. More specifically, the present, invention relates to a data compression technology (i.e., high efficiency codic technology) of the back chorus part, a pitch shift technology of the back chorus part and a synthesis technology of the back chorus part, all of which are directed to savings of the karaoke song data volume.
A karaoke apparatus is constructed such as to produce an instrumental accompaniment part of a requested karaoke song, which is concurrently mixed with a live vocal part of the same song picked up by a microphone. The karaoke apparatus has become popular, and is installed not only in a bar and a club, but also in a specialized rental room called a "karaoke box" and a vehicle such as a tourist bus. The conventional karaoke apparatus is normally a playback type or a musical tone reproduction type composed of a record unit for recording audio information and associated video information of karaoke songs, an audio unit for reproducing the karaoke song find mixing a singing voice therewith, a video unit for displaying background pictures and lyric word characters along with the reproduction of the karaoke song and a control unit for controlling the record, audio and video units. Recently, another karaoke apparatus of a synthetic type or a musical tone generating type was developed, which contains a tone generator for synthesizing musical tones according to a song data prescriptive of the karaoke song. Generally, the synthetic karaoke apparatus is connected through a communication network to a host station for retrieving therefrom the song data.
The playback karaoke apparatus has the record unit which is a closed or isolated data source, hence the playback karaoke apparatus cannot respond to a request for a non-entry karaoke song which is not stored in the record unit. On the other hand, the synthetic karaoke apparatus can access a database of the host station to freely retrieve therefrom a desired song data in response to a singer's request. An ultimate type of the synthetic karaoke apparatus is solely dependent on the data telecommunication such that all the requested song data are supplied from the host station without exception. In order to save data communication cost and time required for repeated access to the host station upon every request, a semi-self-support type of the synthetic karaoke apparatus has a storage defining an open data source for stocking the song data supplied from the host station for re-use.
The karaoke apparatus may sound a karaoke song containing a back chorus (i.e., a background harmony by human voices) in addition to the instrumental accompaniment in order to enhance an amusement of the karaoke performance. The back chorus is generally classified into a general or common chorus and a specific or phrase chorus. The common chorus is composed of a rather simple sound like a combination of a short consonant and a prolonged vowel such as "WAAA-" and "RAAA-" which may be repeatedly added in the same song, or a train of simple voices such as "WAAWAAWAA-" or "WA, WA, WA,-" which may be used for different songs. On the other hand, the phrase chorus is composed of a particular phrase such as "NAGASAKIWAAA" specific to a requested song. Generally, the back chorus requires a great data volume as compared to the instrumental accompaniment so that the total data volume of the karaoke song is considerably expanded if the back chorus is introduced. However, the total data volume of each karaoke song should be reduced as much as possible in the synthetic karaoke apparatus in order to save the telecommunication cost and time of the karaoke song data and to save a capacity of the data storage. The synthetic karaoke apparatus has an advantage over the playback karaoke apparatus in that the tone generator is installed to synthesize the instrumental accompaniment based on the concise song data. However, the addition of the back chorus may obviate the advantage of the synthetic karaoke apparatus.